public void ShouldInvokeWalletAndReturnAmountRemainingForShopping()
        {
            var mockWallet = new Mock<IWallet>();
            mockWallet.Setup(wallet => wallet.CalculateAmountRemainingForShopping(4)).Returns(6);
            shoppingCostAnalyser = new ShoppingCostAnalyser(mockWallet.Object);

            Assert.That(shoppingCostAnalyser.GetAmountRemainingForShopping(4), Is.EqualTo(6));

            mockWallet.Verify(wallet => wallet.CalculateAmountRemainingForShopping(4));
        }
 public void SetUp()
 {
     shoppingCostAnalyser = new ShoppingCostAnalyser(new Wallet(0.0));
 }